A water discharger, also referred to as drain device, is proposed for storing or discharging water in containers such as bathroom, tub, washbasin or hand-washing sink. Such drain device is generally in form of a drain plug linkage device. For instance, in a prior art drain device, the container is in communication with a drainpipe through an outlet, and a drain plug is disposed adjacent to the outlet and connected with one end of an operating rod such as a lever member, and the other end of the lever member is connected with a pull rod member extending downwards, so as to move the drain plug between positions of closing and opening the outlet by operating the pull rod member, realizing water storage or discharge in the containers like bathroom pool, tub, washbasin or hand-washing sink.
A number of the drain devices, namely drain plug linkage devices, have been known in the prior art.
For example, U.S. Pat. No. 4,903,943 discloses a linkage mechanism for a discharge valve, in which a spherical part is fixed on a lever member such that the lever member can perform a lever motion about the spherical part as a pivot point. The lever member is connected at one end with a pull rod member via a connecting member, and at the other end with a drain plug, while the connecting member at one end is pivotally and undetachably connected with the lever member by means of a pin, and at the other end is secured to a position of the pull rod member by means of a screw, such that an operative connection between the pull rod member and lever member is realized, so as to perform opening or closing movement of the drain plug by pulling the pull rod member upwards or downwards. It is fairly difficult to assemble such a linkage mechanism, since a number of small components have to be mounted in a limited space. Furthermore, the connecting member is prone to rust, which will be detrimental to operation of the linkage mechanism. Moreover, the pull rod member of the linkage mechanism is mainly made from rigid rod pieces, which results in lack of degree of freedom during transition from a vertical lift movement of the pull rod to a vertical lift movement of the drain plug via the lever action. In addition, difficulty occurs in mounting a locking nut by means of which the spherical part is directly and pivotably mounted in the pipe body of the discharge valve.
U.S. Pat. No. 6,061,847 discloses a linkage assembly for a drain stopper, including an elongated connector bar having a plurality of apertures at both its upper and lower ends, a stem having a J-shaped portion, a lever arm, and a drain stopper having an aperture, wherein the J-shaped portion of the stem is received within a select aperture at the upper end of the connector bar, and the lever arm at one end is inserted in a select aperture at the lower end of the connector bar, and at the other end is inserted in the aperture of the drain stopper. The linkage assembly is operated with a higher degree of freedom and assembled more easily, as compared with that of U.S. Pat. No. 4,903,943. However, no positioning effect can be provided by the connection among the J-shaped portion of stem, the apertures of connector bar and the lever arm in the linkage assembly, such that an effective opening and closing movement of the drain stopper may not be realized by said linkage assembly.
U.S. Pat. No. 8,136,179 B2 discloses a drain stopper linkage assembly, including a lift rod, a connecting bar, a pivot rod and a drain stopper, wherein the bottom end of the lift rod forms an engagement part, the upper end of the connecting bar has an engagement groove for the engagement part of the lift rod being engaged and fixed, the connecting bar has a plurality of holes, the pivot rod at one end has concave arc fixed portions for tying in with the hole, and a convex arc portion disposed between two said fixed portions, and an outer diameter of the pivot rod adjacent the end is slightly larger than an inside diameter of the holes of the connecting bar. In the drain stopper linkage assembly, the connecting bar is connected with the lift rod and the pivot rod both in form of snapping, which improves accuracy of positioning. Nevertheless, a considerable force for disengaging the snapping connection needs to be overcome, which results in, e.g., difficulty in adjusting the positions of the connecting bar relative to the pivot rod and also in disengaging the lift rod from the connecting bar, meanwhile causes wear of components in the linkage assembly easily, and shortens service life of the linkage assembly. Moreover, a spherical body of the pivot rod in the linkage assembly is still directly mounted in a pipe via a locking nut, causing difficulty in assembly in the limited space.
Therefore, there is need to improve the prior drain plug linkage devices, with advantages of simple and reliable assembly and disassembly, easy adjustment and reliable operation of the drain plug linkage device.